The process of transferring the domain owner from one registrar to another is usually implemented according to the rules of the registrar where the domain was previously purchased. As a rule, for such a procedure, it is necessary to provide documents confirming the identity of the current owner.
That is, if the domain is currently registered to your contractor, you need to provide his documents and yours as the new owner, and complete the Hong Kong Email List process of transferring the rights to the domain. How to transfer a domain We will describe in general terms how domain rights are

We do not give an example of a specific registrar, because the procedure may differ, but in general the algorithm is similar. The difference may be only in the specifics of the registrar itself or your situation with the former and new owner of the domain. Select the new domain name registrar where you want to transfer your domain.